Hello Ev,
I think you are right. I looked at the parish record and Alexander Rowan was illegitimate. The informant was Duncan Cameron, Governor. I suppect he is the same Duncan Cameron "General Of Poor House" in the 1871 census of Kilmore and Kilbride. One of the tenants in the poor house is an orphan named Alexander Rowan (transcribed as Rossan on Ancestry.com), age 5 born Kibride or Kilmore (hard to say which as it looks like one word written over the other).
Thanks!
Colin